The present invention relates to electrically-operated physical security alarm systems, and particularly to application of such systems to protect hingemounted doors including glass panels.
In the past, security alarm circuits have protected windows mounted on hinges, and doors including windows, by the use of metal foil tape attached to the glass so as to fracture, opening an electrical circuit if the glass is broken. In order to connect such metal foil conductors to the portion of an alarm circuit extending from such a door to an alarm control panel or the like, a flexible jumper cable has been connected loosely between the door and a portion of the alarm system circuit fastened to supporting structure located adjacent the door. A problem in this arrangement has been that the electrical conductors contained within such a cable break, causing false alarms, frequently within a short period after installation. This may occur because of stress concentrations at the ends of the loosely suspended portion of the cable extending between the door and its doorway frame, as the result of the cable being accidentally caught by objects being carried through the doorway, or because of the cable being pinched as the door is closed.
Another problem associated wit such a jumper cable used to connect a glass-protecting circuit to the remainder of an alarm circuit is that the jumper cable is visibly exposed, providing an unattractive appearance and offering an attractive target for tampering.
Security alarm systems detect unauthorized opening of doors by the use of sensors often including magnetically-actuated switches in either normally-open or normally-closed circuit arrangements. Connection of such sensors to an alarm system intrusion detection circuit to protect a door has previously required a switch housing to be mounted in a doorway, and has also, depending on the type of switch installed, in some cases required a magnet to be mounted on the door to be protected. As a result, the installation of switches, magnets, and jumper cables to fully protect a door having glass panels has previously required an undesirably long time, resulting in undesirably high labor costs.
What is needed, therefore, is a connector assembly providing for a reliable connection between alarm system intrusion detection circuits and a hinge-supported window or a door having windows, which will provide for detection of both opening the window or door and breakage of the glass, which will provide protection against tampering and inadvertent damage, and which will provide a better appearance than the previously used loosely hanging exposed jumper cables.